1 # SPDX-License-Identifier: (GPL-2.0-only OR BS 1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 # Copyright (C) 2020 BAIKAL ELECTRONICS, JSC 2 # Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
3 %YAML 1.2 3 %YAML 1.2
4 --- 4 ---
5 $id: http://devicetree.org/schemas/clock/baika 5 $id: http://devicetree.org/schemas/clock/baikal,bt1-ccu-div.yaml#
6 $schema: http://devicetree.org/meta-schemas/co 6 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 7
8 title: Baikal-T1 Clock Control Unit Dividers 8 title: Baikal-T1 Clock Control Unit Dividers
9 9
10 maintainers: 10 maintainers:
11 - Serge Semin <fancer.lancer@gmail.com> 11 - Serge Semin <fancer.lancer@gmail.com>
12 12
13 description: | 13 description: |
14 Clocks Control Unit is the core of Baikal-T1 14 Clocks Control Unit is the core of Baikal-T1 SoC System Controller
15 responsible for the chip subsystems clocking 15 responsible for the chip subsystems clocking and resetting. The CCU is
16 connected with an external fixed rate oscill 16 connected with an external fixed rate oscillator, which signal is transformed
17 into clocks of various frequencies and then 17 into clocks of various frequencies and then propagated to either individual
18 IP-blocks or to groups of blocks (clock doma 18 IP-blocks or to groups of blocks (clock domains). The transformation is done
19 by means of an embedded into CCU PLLs and ga 19 by means of an embedded into CCU PLLs and gateable/non-gateable dividers. The
20 later ones are described in this binding. Ea 20 later ones are described in this binding. Each clock domain can be also
21 individually reset by using the domain clock 21 individually reset by using the domain clocks divider configuration
22 registers. Baikal-T1 CCU is logically divide 22 registers. Baikal-T1 CCU is logically divided into the next components:
23 1) External oscillator (normally XTAL's 25 M 23 1) External oscillator (normally XTAL's 25 MHz crystal oscillator, but
24 in general can provide any frequency supp 24 in general can provide any frequency supported by the CCU PLLs).
25 2) PLLs clocks generators (PLLs). 25 2) PLLs clocks generators (PLLs).
26 3) AXI-bus clock dividers (AXI) - described 26 3) AXI-bus clock dividers (AXI) - described in this binding file.
27 4) System devices reference clock dividers ( 27 4) System devices reference clock dividers (SYS) - described in this binding
28 file. 28 file.
29 which are connected with each other as shown 29 which are connected with each other as shown on the next figure:
30 30
31 +---------------+ 31 +---------------+
32 | Baikal-T1 CCU | 32 | Baikal-T1 CCU |
33 | +----+------|- MIPS P5600 cores 33 | +----+------|- MIPS P5600 cores
34 | +-|PLLs|------|- DDR controller 34 | +-|PLLs|------|- DDR controller
35 | | +----+ | 35 | | +----+ |
36 +----+ | | | | | 36 +----+ | | | | |
37 |XTAL|--|-+ | | +---+-| 37 |XTAL|--|-+ | | +---+-|
38 +----+ | | | +-|AXI|-|- AXI-bus 38 +----+ | | | +-|AXI|-|- AXI-bus
39 | | | +---+-| 39 | | | +---+-|
40 | | | | 40 | | | |
41 | | +----+---+-|- APB-bus 41 | | +----+---+-|- APB-bus
42 | +-------|SYS|-|- Low-speed Devices 42 | +-------|SYS|-|- Low-speed Devices
43 | +---+-|- High-speed Device 43 | +---+-|- High-speed Devices
44 +---------------+ 44 +---------------+
45 45
46 Each sub-block is represented as a separate 46 Each sub-block is represented as a separate DT node and has an individual
47 driver to be bound with. 47 driver to be bound with.
48 48
49 In order to create signals of wide range fre 49 In order to create signals of wide range frequencies the external oscillator
50 output is primarily connected to a set of CC 50 output is primarily connected to a set of CCU PLLs. Some of PLLs CLKOUT are
51 then passed over CCU dividers to create sign 51 then passed over CCU dividers to create signals required for the target clock
52 domain (like AXI-bus or System Device consum 52 domain (like AXI-bus or System Device consumers). The dividers have the
53 following structure: 53 following structure:
54 54
55 +--------------+ 55 +--------------+
56 CLKIN --|->+----+ 1|\ | 56 CLKIN --|->+----+ 1|\ |
57 SETCLK--|--|/DIV|->| | | 57 SETCLK--|--|/DIV|->| | |
58 CLKDIV--|--| | | |-|->CLKLOUT 58 CLKDIV--|--| | | |-|->CLKLOUT
59 LOCK----|--+----+ | | | 59 LOCK----|--+----+ | | |
60 | |/ | 60 | |/ |
61 | | | 61 | | |
62 EN------|-----------+ | 62 EN------|-----------+ |
63 RST-----|--------------|->RSTOUT 63 RST-----|--------------|->RSTOUT
64 +--------------+ 64 +--------------+
65 65
66 where CLKIN is the reference clock coming ei 66 where CLKIN is the reference clock coming either from CCU PLLs or from an
67 external clock oscillator, SETCLK - a comman 67 external clock oscillator, SETCLK - a command to update the output clock in
68 accordance with a set divider, CLKDIV - cloc 68 accordance with a set divider, CLKDIV - clocks divider, LOCK - a signal of
69 the output clock stabilization, EN - enable/ 69 the output clock stabilization, EN - enable/disable the divider block,
70 RST/RSTOUT - reset clocks domain signal. Dep 70 RST/RSTOUT - reset clocks domain signal. Depending on the consumer IP-core
71 peculiarities the dividers may lack of some 71 peculiarities the dividers may lack of some functionality depicted on the
72 figure above (like EN, CLKDIV/LOCK/SETCLK). 72 figure above (like EN, CLKDIV/LOCK/SETCLK). In this case the corresponding
73 clock provider just doesn't expose either sw 73 clock provider just doesn't expose either switching functions, or the rate
74 configuration, or both of them. 74 configuration, or both of them.
75 75
76 The clock dividers, which output clock is th 76 The clock dividers, which output clock is then consumed by the SoC individual
77 devices, are united into a single clocks pro 77 devices, are united into a single clocks provider called System Devices CCU.
78 Similarly the dividers with output clocks ut 78 Similarly the dividers with output clocks utilized as AXI-bus reference clocks
79 are called AXI-bus CCU. Both of them use the 79 are called AXI-bus CCU. Both of them use the common clock bindings with no
80 custom properties. The list of exported cloc 80 custom properties. The list of exported clocks and reset signals can be found
81 in the files: 'include/dt-bindings/clock/bt1 81 in the files: 'include/dt-bindings/clock/bt1-ccu.h' and
82 'include/dt-bindings/reset/bt1-ccu.h'. Since 82 'include/dt-bindings/reset/bt1-ccu.h'. Since System Devices and AXI-bus CCU
83 are a part of the Baikal-T1 SoC System Contr 83 are a part of the Baikal-T1 SoC System Controller their DT nodes are supposed
84 to be a children of later one. 84 to be a children of later one.
85 85
86 if: 86 if:
87 properties: 87 properties:
88 compatible: 88 compatible:
89 contains: 89 contains:
90 const: baikal,bt1-ccu-axi 90 const: baikal,bt1-ccu-axi
91 91
92 then: 92 then:
93 properties: 93 properties:
94 clocks: 94 clocks:
95 items: 95 items:
96 - description: CCU SATA PLL output clo 96 - description: CCU SATA PLL output clock
97 - description: CCU PCIe PLL output clo 97 - description: CCU PCIe PLL output clock
98 - description: CCU Ethernet PLL output 98 - description: CCU Ethernet PLL output clock
99 99
100 clock-names: 100 clock-names:
101 items: 101 items:
102 - const: sata_clk 102 - const: sata_clk
103 - const: pcie_clk 103 - const: pcie_clk
104 - const: eth_clk 104 - const: eth_clk
105 105
106 else: 106 else:
107 properties: 107 properties:
108 clocks: 108 clocks:
109 items: 109 items:
110 - description: External reference cloc 110 - description: External reference clock
111 - description: CCU SATA PLL output clo 111 - description: CCU SATA PLL output clock
112 - description: CCU PCIe PLL output clo 112 - description: CCU PCIe PLL output clock
113 - description: CCU Ethernet PLL output 113 - description: CCU Ethernet PLL output clock
114 114
115 clock-names: 115 clock-names:
116 items: 116 items:
117 - const: ref_clk 117 - const: ref_clk
118 - const: sata_clk 118 - const: sata_clk
119 - const: pcie_clk 119 - const: pcie_clk
120 - const: eth_clk 120 - const: eth_clk
121 121
122 properties: 122 properties:
123 compatible: 123 compatible:
124 enum: 124 enum:
125 - baikal,bt1-ccu-axi 125 - baikal,bt1-ccu-axi
126 - baikal,bt1-ccu-sys 126 - baikal,bt1-ccu-sys
127 127
128 reg: 128 reg:
129 maxItems: 1 129 maxItems: 1
130 130
131 "#clock-cells": 131 "#clock-cells":
132 const: 1 132 const: 1
133 133
134 "#reset-cells": 134 "#reset-cells":
135 const: 1 135 const: 1
136 136
137 clocks: 137 clocks:
138 minItems: 3 138 minItems: 3
139 maxItems: 4 139 maxItems: 4
140 140
141 clock-names: 141 clock-names:
142 minItems: 3 142 minItems: 3
143 maxItems: 4 143 maxItems: 4
144 144
145 additionalProperties: false 145 additionalProperties: false
146 146
147 required: 147 required:
148 - compatible 148 - compatible
149 - "#clock-cells" 149 - "#clock-cells"
150 - clocks 150 - clocks
151 - clock-names 151 - clock-names
152 152
153 examples: 153 examples:
154 # AXI-bus Clock Control Unit node: 154 # AXI-bus Clock Control Unit node:
155 - | 155 - |
156 #include <dt-bindings/clock/bt1-ccu.h> 156 #include <dt-bindings/clock/bt1-ccu.h>
157 157
158 clock-controller@1f04d030 { 158 clock-controller@1f04d030 {
159 compatible = "baikal,bt1-ccu-axi"; 159 compatible = "baikal,bt1-ccu-axi";
160 reg = <0x1f04d030 0x030>; 160 reg = <0x1f04d030 0x030>;
161 #clock-cells = <1>; 161 #clock-cells = <1>;
162 #reset-cells = <1>; 162 #reset-cells = <1>;
163 163
164 clocks = <&ccu_pll CCU_SATA_PLL>, 164 clocks = <&ccu_pll CCU_SATA_PLL>,
165 <&ccu_pll CCU_PCIE_PLL>, 165 <&ccu_pll CCU_PCIE_PLL>,
166 <&ccu_pll CCU_ETH_PLL>; 166 <&ccu_pll CCU_ETH_PLL>;
167 clock-names = "sata_clk", "pcie_clk", "e 167 clock-names = "sata_clk", "pcie_clk", "eth_clk";
168 }; 168 };
169 # System Devices Clock Control Unit node: 169 # System Devices Clock Control Unit node:
170 - | 170 - |
171 #include <dt-bindings/clock/bt1-ccu.h> 171 #include <dt-bindings/clock/bt1-ccu.h>
172 172
173 clock-controller@1f04d060 { 173 clock-controller@1f04d060 {
174 compatible = "baikal,bt1-ccu-sys"; 174 compatible = "baikal,bt1-ccu-sys";
175 reg = <0x1f04d060 0x0a0>; 175 reg = <0x1f04d060 0x0a0>;
176 #clock-cells = <1>; 176 #clock-cells = <1>;
177 #reset-cells = <1>; 177 #reset-cells = <1>;
178 178
179 clocks = <&clk25m>, 179 clocks = <&clk25m>,
180 <&ccu_pll CCU_SATA_PLL>, 180 <&ccu_pll CCU_SATA_PLL>,
181 <&ccu_pll CCU_PCIE_PLL>, 181 <&ccu_pll CCU_PCIE_PLL>,
182 <&ccu_pll CCU_ETH_PLL>; 182 <&ccu_pll CCU_ETH_PLL>;
183 clock-names = "ref_clk", "sata_clk", "pc 183 clock-names = "ref_clk", "sata_clk", "pcie_clk",
184 "eth_clk"; 184 "eth_clk";
185 }; 185 };
186 # Required Clock Control Unit PLL node: 186 # Required Clock Control Unit PLL node:
187 - | 187 - |
188 ccu_pll: clock-controller@1f04d000 { 188 ccu_pll: clock-controller@1f04d000 {
189 compatible = "baikal,bt1-ccu-pll"; 189 compatible = "baikal,bt1-ccu-pll";
190 reg = <0x1f04d000 0x028>; 190 reg = <0x1f04d000 0x028>;
191 #clock-cells = <1>; 191 #clock-cells = <1>;
192 192
193 clocks = <&clk25m>; 193 clocks = <&clk25m>;
194 clock-names = "ref_clk"; 194 clock-names = "ref_clk";
195 }; 195 };
196 ... 196 ...
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.